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## AliTPCSpaceCharge class

// The class calculates the space point distortions due to a rotational // symmetric space charge distribution with the TPC drift volume. //

// The class uses the PoissonRelaxation2D to calculate the resulting // electrical field inhomogeneities in the (r,z)-plane. Then, the // Langevin-integral formalism is used to calculate the space point distortions. //

// The class assumes, that the distortions scales linearly with the magnitude // of the space charge distribution $\rho(r,z)$. The in here assumed distribution is // $$\rho(r,z) = \frac{(A-B\,z)}{r^2}$$ wherein the factors A and B scale with the // event multiplicity and the interaction rate. //

// The scaling factor can be set via the function SetCorrectionFactor. An example of // the shape of the distortions is given below. // End_Html // // Begin_Macro(source) // { // gROOT->SetStyle("Plain"); gStyle->SetPalette(1); // TCanvas *c2 = new TCanvas("c2","c2",500,300); // AliTPCSpaceCharge sc; // sc.SetOmegaTauT1T2(-0.32,1,1); // B=0.5 Tesla // sc.SetCorrectionFactor(0.0015); // sc.CreateHistoDRinZR(0.)->Draw("surf2"); // return c2; // } // End_Macro // // Begin_Html //

// Date: 23/08/2010